Abstract: We investigate a model of a vector massive spinless Bose field in the space interacting with a non-relativistic particle, where the interaction parameter is assumed to be sufficiently small. We study the ground state of the Hamiltonian for a fixed total momentum of the system and show that such a state is non-degenerate and exists only for a bounded domain of values of this momentum. We also show that, apart from the ground state, the operator has no other eigenvalues below the continuous spectrum. Furthermore, the next two, ``one-boson'', branches of the spectrum of are constructed, which describe the scattering of one boson (with two possible polarization values) on the ground state.